One spring evening in 2016, Lee Niegelsky’s underarm began to itch. An investment manager, he was doing housework around his condo, and he thought he’d been bitten by a chigger. But within 15 minutes, hives had erupted all over his body. He responded with what he calls a “typical man reaction” — if the hives didn’t clear up by the next day, he would have them checked. Fifteen minutes later, the itch had become unbearable. He needed help right away.